Method and apparatus for processing, digitally recording and retrieving a plurality of video signals

ABSTRACT

A method and apparatus for processing and digital recording video signal where transmitters for generating video signals receive an external synchronizing signal for synchronizing the transmitters. A recorder receiving the video signals has a switch sequentially connecting the transmitters to a digital video recorder. Code signals corresponding to identification codes allotted to video signals are generated. An injection circuit mixes code signals into video signals. The digital video recorder has a copy including circuit for time and date signal generating, for compressing the received signals and outputting them with the extracted codes and time and date of recorder signals to a memory storing those signals in endless cascaded rotation. Freshly stored signals replace the oldest signals stored in cascade. An alarm data signal for triggering the alarm state of the apparatus is received and the video signals recorded during the alarm state are recorded.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to an apparatus for processing televisioncamera signals used in close circuit television for recording andmonitoring system.

[0003] 2. Description of the Prior Art

[0004] In a monitoring television system used, as one of informationtransmission systems, at least one video cassette recorder or a digitalvideo recorder is connected through an electronic switch to a pluralityof television cameras and transmission lines. The electronic switchprovides for a fast rate sequential switching for recording onto thevideo recorder a picture image of one camera after another.

[0005] In such an information transmission system, it is preferable tomutually lock the internal synchronizing signals of a plurality oftelevision cameras and the electronic switching time to an externalsynchronizing signal, in order to prevent the recording from beingdisturbed during and immediately after the switching operation from onetelevision camera to another.

[0006] A known apparatus for synchronizing a plurality of televisioncameras is an apparatus for transmitting an external synchronizingsignals from an external synchronizing generator to the televisioncameras by injecting the external synchronizing signal into the videosignal transmission line and locking an internal synchronizing signalgenerator of the television camera by means of the transmitted externalsynchronizing signal. Such an apparatus is disclosed in U.S. Pat. No.4,603,352 the contents of which are incorporated herein by reference.

[0007] Another known apparatus for synchronizing the plurality of thetelevision camera signals is an apparatus for memorizing each of thetelevision camera signal in a memory circuit and feeding the signals tothe video recorder, synchronously via the electronic switch from thememory circuits. Such an apparatus is disclosed in U.S. Pat. No.5,267,039 the content of which are incorporated herein by reference.

[0008] Furthermore, the known apparatuses for recording a plurality ofcamera signals at fast sequencing rate require that each individualcamera signal will incorporate coded identification signals, providingfor a simple retrieval of the signal through a coded selection. In thecase of using analog video cassette recorder, the coded identificationis known to be recorded during the vertical blanking period of thetelevision signals, but in the case of using a digital video recorder itis known that digital video recorders ignore the vertical blankingperiod and instead they employ a complex control software for indexingthe files of the recorded digital signals of each individual camera.

[0009] Because the software programs for controlling the individualfiles of the digitally recorded camera signals are complex, it rendersthe processing, transferring and/or retrieval of the recorded digitalsignals to and from disks, tapes or other medium time consuming.Moreover, because of the limited capacity of the digital recorder'sstorage medium the digital video recorders record in a continuous FIFO(First In First Out) rotation, and it is necessary to introduceprotection software programs for the recorded alarms or event files inorder to retain such recording for extended periods by excluding suchalarms and events files from the FIFO process. The continued randomlychanging, deletion and/or addition of protected files causes anextremely complex and inefficient FIFO recording in rotation,particularly when large numbers of television cameras are used.Moreover, the complexity of the software programs makes it literallyimpossible to combine plurality of digital recorders for increasing theoverall storage capacity.

[0010] In another known digital recording system, a plurality of camerasignals are processed in parallel instead of being sequentially switchedand are stored in individual files within the digital recorder storagemedium, but due to the limited storage capacity the recording is alsoprocessed in FIFO rotation and similar file protection software programsare necessary. The complexity of such programs for managing large numberof files in the FIFO rotation and the continuous changes and addition tothe protection files makes the software for the system managementlaborious, costly and inefficient. Here too the complexity of thesoftware programs along with the plurality of input connectors makes itliterally impossible and/or prohibitively expensive to interconnectand/or combine multiple digital recorders in order to increase theoverall storage capacity.

SUMMARY OF THE INVENTION

[0011] It is the object of the present invention to provide a method andan apparatus for a continuous digital recording of a sequentiallyswitched or parallely fed plurality of camera signals in a simple,uninhibited rotation into a single standalone digital recorder or intomultiple, cascaded digital recorders and to retrieve any of the recordedimages on the basis of the recorded time and date and without the needto search complex arrays of files for any specific recorded file orfiles pertaining a specific camera or cameras.

[0012] According to the present invention a method for processing,recording and retrieving video signals generated by a plurality ofsynchronized video transmitters, each incorporating an individuallyallotted identification code signal, into and from a digital recorderhaving at least one main memory storage device for routinely recordingthe camera signals in endless rotation, and an exclusive memory devicefor storing and retaining camera signals recorded during alarms and analarm signal input, comprises the steps of detecting an identificationcode of each individual video signal and compressing the video signalsone after another in sequence or in parallel and storing the compressedindividual signals along with the individual identification code thereofand the time and date of the recording in a continuous cycle into atleast one main memory storage device to full capacity, one after anotherin endless cascaded rotation, wherein freshly processed signals replacethe oldest stored signals. Identifying the individual code signals andtime and date of the recorded video signals related to inputted alarmsignals and/or to pre-alarm, and/or post alarm time and transferring orduplicating the recorded camera signals related to the inputted alarmsignals into the exclusive alarm memory device which is excluded fromroutine recording in the endless cascaded rotation, protects the alarmrelated recordings from routine erasure and retaining the alarm relatedrecordings for future playback. The routinely recorded camera signalsand/or the alarm related camera signals are played back by retrievingthe recorded signals from the main storage device and/or the exclusivestorage device on the basis of the recording time and date and/or thestored identification code or codes and/or the inputted alarm signals,decompressing the signals and re-injecting the identification codesignals with the time and date signals, into the vertical blankingportion of the decompressed outputted video signals.

[0013] The method for processing, recording and retrieving video signalsfurther comprises the steps of combining a plurality of said digitalrecorders in a cascaded recording rotation for enlarging the totalrecording capacity, wherein each of the cascaded digital recorders,records to its full capacity in rotation one after another in endlesscascaded rotation, and wherein freshly processed signals replace theoldest stored signals.

[0014] Recalling for playback any recorded individual camera signalsthrough any of the cascaded digital recorder is achieved through aplayback receiving means adapted to select an individual signal fromserially fed sequencing signals by generating a selection command on thebasis of the recalled camera identification, the time and date of therecording and/or alarm particulars.

[0015] An apparatus for processing, recording and retrieving a signalaccording to the present invention comprises a receiving means includinga plurality of transmitting means, for generating analog or digitalvideo signals incorporating an identification code signal allotted toeach transmitting means; an external synchronizing generator forgenerating an external synchronization signal for synchronizing internalsynchronizing generators of the transmitting means and the receivingmeans, a recording receiver including an electronic switch for receivingthe video signals transmitted from said transmitting means, forprocessing and feeding the video signals sequentially through anelectronic switch in rotation one after another at a predetermined rateand time to the recording means, or for converting parallel processedsignals into serial digital signals and feeding the processed signals tothe recording means; a recording means for recording and storing theprocessed video signals received from the receiving means along withidentification codes and the time and date of the recording and forplaying back the stored signals and outputting the played back signals;an encoding/decoding means for extracting and decoding theidentification code signal of the video signals fed from the receivingmeans and for encoding and injecting newly the identification signalsalong with the time and date into a vertical blanking portion of theplayed back signals; a selector means for setting a selector codecommensurate with a code allotted to each transmitting means foroutputting a code select command and at least of a time and date selectcommand, and feeding outputted commands to the recording means forrecalling playback signals for at least one of specific time, specificdate and specific coded signals; and a monitor to display the image ofthe retrieved video signal from the recording means.

[0016] Each of the transmitting means includes a television camera towhich an identification code is allotted. The television may incorporatea circuit for generating code signals corresponding to theidentification code, and a circuit for generating a signal wherein thecode signals are injected into the video signal. Such an apparatus isdisclosed in U.S. Pat. No. 4,943,864, the contents of which areincorporated herein by reference.

[0017] Alternatively, the allotted identification code signals can begenerated by code generators for injecting a code signal into the videosignal along each individual transmission line or by a code generatorand code mixing circuits incorporated in the recording receiver forinjecting a code into the output video signals coordinated and inconcert with the switching means, or by generating and injecting thecode signals into the multi-input processor of the recording receiver.

[0018] The switching means may include an electronic switch forconnecting the video signals fed from the transmitting means in aselectable, predetermined, time and rate sequence, for feeding theindividual coded video signals one after another to the recording means.It is preferable that the switching rate will commensurate with thefrequency of the vertical period of the video signal, and that thepredetermined time is at least one vertical period of the video signal.

[0019] When the video signals generated by the transmitting means areanalog signals and the transmitting means are not externallysynchronized, the recording receiver may include at least one of a syncseparator circuit, an analog to digital converter, and a memory circuitfor reorganizing the time base of the inputted signals, such, that thevideo signals processed within the recording receiver and sequentiallyswitched by the switching means are in tandem with the external sync.generator.

[0020] The recording means may include a circuit for compressing thereceived video signals and outputting the compressed signals to thememory means, a circuit for decompressing the retrieved stored signalsand a circuit for converting the decompressed signals to a video signalalong with a circuit for injecting the identification code signal andthe time and date into the vertical blanking portion of the videosignals.

[0021] The recording means may further include a CPU (central processingunit) for processing and controlling the different circuits, the timeand date, and other functions of the digital recording process and forcontrolling the memory devices used for storing the digital signalsthrough a memory system control circuit.

[0022] The CPU is fed with key commands or remote commands or by analarm input signals through a control in terminal or terminals and feedsan output control command through an output control terminal forcombining in a cascaded connection a plurality of recording means forincreasing the capacity of the recording means.

[0023] The CPU is provided with means for setting a coded station numberto the recording means for enabling a simple addressing of a specificrecording means for recalling playback signals from the cascaded chainof recording means, or for addressing a specific recording means of thecascaded chain connected along with pluralities of cascaded chains, to aplayback receiver means.

[0024] A cascaded chain of the recording means may include a videodistributor to distribute the video signals outputted from the receivingmeans to the plurality of the recording means in the cascaded chain, acontrol unit for connecting in a cascaded chain the control in-outterminals of the recording means and to an alarm input signal, and aselector for connecting the outputs of the recording means of thecascaded chain and feeding a selective output to the playback receivermeans.

[0025] The playback receiver means may include a selector and a circuitfor setting a selector code, a circuit for extracting and decoding theidentification code signal from the received video signal, and a circuitto retrieve from the sequencing video signals received from therecording means, the selected video signal, and output the retrievedvideo signal to a television monitor.

[0026] The playback receiver means may include a circuit for generatingdisplays onto the monitor screen known as the OSD (on screen display)circuit for displaying on command the identification number of theselected camera or its name and/or text related to the decodedidentification number, and a memory circuit for recording and retainingthe text and/or names of the identification code number used for theplurality of cameras connected to any of the digital recording means ofa digital recording system setup.

[0027] The OSD circuit along with the identification decoding circuitfurther provides the decoding of the time and date contained in thevertical blanking portion of the extracted signal and the display, uponcommand, of the time and date of the recording of the played back videosignal.

[0028] The playback receiver means may further include a playbackcontrol circuit for feeding control signals to the digital recordermeans for selecting a playback signal from any of the connected digitalrecorder means on the basis of a camera identification code, the cameraname, the time and date of the recording, an alarm input signal and orany of cascaded chain of digital recorder means or individual digitalrecorder means through the station identification code thereof therebyproviding a simple playback selection for any number of digital recordermeans, connected individually or from a plurality of cascaded chains.

BRIEF DESCRIPTION OF THE DRAWING

[0029] The foregoing and other objects and features of the inventionwill become apparent from the following description of preferredembodiments of the invention with reference to the accompanyingdrawings, in which:

[0030]FIG. 1 is a block diagram showing an electric circuit forprocessing digital recording, and retrieving signal apparatus of thepreferred embodiment according to the present invention;

[0031]FIG. 2 is a block diagram showing an electric circuit of areceiver including a known externally synchronizing television cameraincorporating a known identification code generating circuit of thepreferred embodiment;

[0032]FIG. 3 is a block diagram showing another electric circuit of anembodiment of the receiver with identification code generating circuitsseparated from the television cameras;

[0033]FIG. 4 is a block diagram showing an electric circuit of yetanother embodiment of the receiver with an identification codegenerating circuit within the receiver;

[0034]FIG. 5 is a block diagram showing an electric circuit of anotherpreferred embodiment of the receiver incorporating a time base correctorand cameras incorporating respective identification code generatingcircuits;

[0035]FIG. 6 is a block diagram showing another preferred embodiment ofthe receiver incorporating the time base corrector and with anidentification code generating circuit within the receiver;

[0036]FIG. 7 is a block diagram showing an electric circuit of thereceiver with a parallel processing circuit and including a knowntelevision camera incorporating an identification code generatingcircuit of the preferred embodiment;

[0037]FIG. 8 is a block diagram showing yet another electric circuit ofreceiver of the preferred embodiment with a parallel processing circuitand with an identification code generating circuit within the receiver;

[0038]FIG. 9 is a block diagram of an electric circuit of a televisioncamera with a well known external synchronization circuit;

[0039]FIG. 10 is a block diagram showing an electric circuit of atelevision camera with an identification code generator of a preferredembodiment of the present invention;

[0040]FIG. 11 is a block diagram showing another embodiment of theidentification code generator circuit of the present invention;

[0041]FIGS. 12A to 12D shows a diagram of an electric signal waveform;

[0042]FIG. 13 is a block diagram showing a selective code processingcircuit as a preferred embodiment of the present invention;

[0043]FIG. 14 is a block diagram showing a further embodiment of thecode extracting circuit of the present invention;

[0044] FIGS. 15A-15C show a diagram showing an electric code signalswaveforms;

[0045]FIG. 16 is a block diagram of an electric circuit of the digitalrecorder of the preferred embodiment of the invention;

[0046]FIG. 17 is a block diagram of an electric circuit showing acascaded setup of the digital recorder of FIG. 16 in a rack of thepreferred embodiment;

[0047]FIG. 18 is a block diagram of an electric circuit showing aplayback receiver of the preferred embodiment of the present invention;and

[0048]FIG. 19 is a block diagram of an electric circuit showing multicascaded setup in a large-scale digital recorder of the preferredembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Referring to FIG. 1, an apparatus 1 for processing, digitallyrecording, and retrieving a plurality of video signals comprises anexternal synchronizing signal generator 6, a plurality of transmitters 2incorporating television cameras 2A synchronized by the externalsynchronizing signal, and generating a video signal corresponding to theimages picked-up by the television cameras, a plurality ofidentification code generators 3A for generating into each video signalgenerated by the transmitters 2 a code signal allotted to eachtransmitter, and a recording receiver 11 for receiving and outputtingvideo signals. The recording receiver 11 of the receiving means 10incorporates a switch S1 as shown in FIG. 2, for connecting sequentiallyin rotation the transmitters 2 to a video out terminal 18 at apredetermined rate and time. Synchronizing pulses fed from the ext.syncgenerator 6 are injected into each of video transmission lines 5 fortransmitting the external synchronizing signal to the television cameras2A, a digital video recorder 30 for recording and playing back videosignals is connected through its input terminal 31 to the sequencingvideo signals generated by the transmitters 2; a code select circuit 39is provided for setting the time and date of the recording and/or a codecommensurate with a code allotted to the transmitters 2, and a monitor60 is provided for displaying an image corresponding to retrieved videosignal.

[0050] As shown in FIG. 9, the television camera 2A is a well-knowntelevision camera synchronized by a synchronizing pulse having a levelhigher than the white level of a composite video signal, as described inU.S. Pat. No. 4,603,352, the contents of which are incorporated hereinby reference.

[0051] The frequency of the external synchronizing signal commensurateswith the frequency of the vertical scanning frequency of the videosignal outputted from the transmitter 2. The frequency of the externalsynchronizing signal may be either of a frame scanning frequency or afield scanning frequency, for example, in case of NTSC system thevertical synchronizing signal frequency is 60 Hz, therefore, the fieldfrequency is 60 Hz and the frame frequency is 30 Hz.

[0052] As shown in FIG. 12A, the time of the external synchronizingsignal P1 is generated adjoins the vertical synchronizing pulse,occurring during the vertical blanking period of the video signaltransmitted from the television camera 2A shown in FIG. 9. Thereby, theexternal synchronizing signal P1 can be fed to the television camera 2Aand through the camera transmission line 5 that propagates the videosignal without affecting the video signal. The voltage level of theexternal synchronizing signal P1 is preferably made higher than thevideo signal. However, the voltage level of the external synchronizingsignal P1 may be lower than the video signal or have a reversedpolarity.

[0053] In the following description, a frame external synchronizingpulse having a voltage level higher than the white level of the videosignal, in particular, a frame external synchronizing pulsecorresponding to the phase of a second field is used as the externalsynchronizing signal P1.

[0054] Accordingly, the television camera 2A (FIG. 9) comprises acomparison circuit 70 for comparing the voltage level of the verticalframe or field synchronizing pulse, fed from external synchronizingsignal generator 6 through the video transmission line 5 to a referencevoltage 71, and generating a pulse signal when a frame or a fieldsynchronizing pulse is equal or higher than the reference voltage, aninternal synchronizing signal generator 72 for receiving the pulsesignal outputted from the comparison circuit 70 and generating aninternal synchronizing signal synchronized with the received pulsesignal, and a video signal generating circuit 74 for generating videosignal.

[0055] One terminal of the comparison circuit 70 is connected to thevideo transmission line 5, and the other terminal of the comparisoncircuit 70 is connected to a reference voltage source 71. The referencevoltage of the reference voltage source 71 has a level higher than thewhite level of the video signal, preferably a level approximately equalto the synchronizing pulse level.

[0056] The internal synchronizing signal generator 72 generateshorizontal and vertical synchronizing signals synchronously with thepulse signal outputted from the comparison circuit 70, synchronizing thevideo signal outputted from the video signal generating circuit 74through the terminal 76 to the video transmission line 5.

[0057] The synchronizing generator 6 of the receiving means 10A shown inFIG. 3 injects the frame or field external synchronization pulses intothe video transmission lines 5/1, connecting the identification codegenerators 3 with the inputs 13/1˜13/n of the switch S1; however, it canbe injected into the video transmission lines 5/2, and as will beexplained, regardless of the locations of where the identification codesignals are injected into the video transmission lines, it is possibleto inject the external synchronizing pulses anywhere along the videotransmission lines, or at the inputs of the switch S1 of the receivingmeans 11.

[0058] When the identification code generators 3 are placed at the sideof the switch circuit S1 then it is possible to inject the frame orfield external synchronizing pulses into the video transmission linesjunction 5/2, thereby, effectively feeding the frame or field externalsynchronizing pulses directly to the input terminal of the comparisoncircuit 70.

[0059] Similarly, if the identification code generators 3 are placedinside the transmitter 2 as shown in FIG. 1, the terminal of thecomparison circuit 70 shown in FIG. 10 is connected directly to thevideo transmission line 5, through terminal 76.

[0060] When the identification code generators 3 are disposed along thevideo transmission line 5, and the external synchronizing pulses are fedto the transmission line 5/1, a comparison circuit 70A shown in FIG. 11is placed across the identification code generator 3 for transferringthe external synchronization pulses from the terminal 77 of the codegenerator 3, connected to the transmission line 5/1 side, to theterminal 78 connected to the television camera 2A via transmission line5/2.

[0061] One input terminal of the comparison circuit 70A is used forcomparing the voltage level of the field or frame synchronizing pulsereceived from the external synchronizing signal generator 6 through thevideo transmission line 5/1 and through terminal 77 to a referencevoltage 71, and regenerating a pulse signal when the synchronizing pulseis equal or higher than the reference voltage. The other input terminalof the comparison circuit 70A is connected to a reference voltage source71, having a voltage level higher than the white level of the compositevideo signal, preferably a level approximately equal with thesynchronizing pulse level.

[0062] The output terminal of the comparison circuit 70A is connected tovideo transmission line 5/2 through terminal 78 for outputting theregenerated pulse, thereby, the comparison circuit 70A is effectively aby-pass or transfer circuit for transferring the field or framesynchronizing pulse across the identification code generator 3 to thetransmitter 2, enabling to dispose the identification code generatoranywhere along the video transmission line 5.

[0063] Since the internal synchronization generator 72 is synchronizedwith the injected external frame of field synchronizing pulse, thesynchronizing pulse presence on the video transmission line 5 is withinthe period corresponding to the vertical blanking interval of the videosignal. In this step, the external frame or field synchronizing pulse istransmitted by the use of the transmission line for the video signalwithout affecting the video signal transmitted from the televisioncamera.

[0064] However, to avoid an input signal level error it is preferable toremove signal levels that are larger than the white level of the videocomposite signal from the video signal reaching the output terminal 18of the recording receiver 11 or the digital recorder 30.

[0065] The external synchronizing generator 6 shown in FIG. 2 generatesand two pulse signals P1 and P2, corresponding to a predetermined rate,width and level, as shown in FIGS. 12A and 12C.

[0066] The phase of the pulse signals P1 and P2 correspond to thevertical blanking interval of the video signal, as shown in FIG. 12B,and, at the same time, the pulse signals P1 and P2 are shown having aframe rate, i.e., generated every second vertical field synchronizingsignals. Further, the frame synchronizing pulse signal P1 has a levelhigher that the white level of the video signal, as shown in FIG. 12Band as the pulse P1 is injected into the video transmission lines 5, thevideo signals fed to the switch inputs 13/1˜1/3n results in a signalshown in FIG. 12B, showing that the pulse signal P1 is injected withinthe period corresponding to the vertical blanking interval.

[0067] The synchronizing pulse P1 is also inputted to the switch pole 12for synchronizing the sequencing operation on the basis of the frame orfield synchronizing pulses.

[0068] The input of a synchronizing pulse clipping circuit 19 is fedwith pulse P2 shown in FIG. 12C for clipping the signal corresponding tothe pulse signal P1 within the video signal fed to the output terminal18 of the receiving means 11, to below or about the black level of thevideo signal as shown in FIG. 12D. Therefore, the pulse P1 is removedfrom the video signal fed to the digital recorder 30 through thesynchronizing pulse clipping circuit 19, and will not influence theinput circuit of the digital recorder 30.

[0069] The single synchronizing pulse clipping circuit 19 shown in FIG.2 is provided for clipping the synchronizing pulse P1 from a signal fedfrom any of the video transmission lines 5 through the output of theselector S1 by using the timing signal P2 to clip the pulse P1 andoutput a video signal containing no synchronizing pulse P1.Alternatively, a plurality of synchronizing pulse clipping circuits 19can be placed at the inputs 13/1˜13/n of the switch S1 each fed with thesignal shown in FIG. 12B from the respective information transmissionline 5 and the timing signal P2 shown in FIG. 12C, thereby clipping theentire signal portion of the signal fed to the input terminal 13/1˜13/nabove the black level of the video signal during the period of signalP2. Since the duration of P2 covers the period of the externalsynchronizing pulse P1 the external synchronizing signal P1 will beremoved by the clipping circuit 19 from the video signal fed to therecording receiver 11. Though the pulse P2 shown in FIG. 12B is apositive pulse any other pulse size and polarity that is timed tocoincide with pulse P1 12(A) can be used to activate the clippingcircuit 19 shown in FIG. 2.

[0070] Accordingly, even though the external synchronizing signal P1 ispresent in the video signal fed from the television camera 2A throughthe transmission line 5 it is removed by the clipping circuit 19,therefore the external synchronizing signal P1 injected into theinformation transmission line 5 will synchronized the television camera2A and will not cause any receiving error at the recording receiver 11.

[0071] Instead of injecting the synchronizing pulse into thetransmission lines the frame synchronizing pulse signal P1 may beoutputted directly to the comparison circuit 70 of the television camera2A.

[0072] In case the television camera 2A is not provided with thecomparison circuit 70, the pulse signal P1 or P2 may by outputted to theinternal synchronizing generator 72 of the television camera 2A. In thelatter case, the synchronizing pulse injection and the synchronizingpulse clipping circuit 19 are not needed.

[0073] In case the television camera 2A is synchronized by the knownhorizontal and vertical synchronizing signal, or by a compositesynchronizing signal known as GENELOCK, or the horizontal and verticaldrive signals, or the vertical drive signal, a generation circuit forthe horizontal and vertical synchronizing signals, or compositesynchronizing signal, or the horizontal and vertical drive signals orthe vertical drive signal may be disposed, instead of the synchronizingpulse generator 6. In this case, the synchronizing pulse injection andthe synchronizing pulse clipping circuit 19 are not needed.

[0074] Moreover, according to the present invention, it is possible toconnect non externally synchronized cameras 2B for processing, digitalrecording and retrieving signal, by using for example, a well known timebase corrector 7 that may include a frame or field memory circuitdisposed at the inputs 13/1˜13/n of the switch circuit S1 as shown inFIGS. 5 and 6, whereby, the time base corrector and/or the frame orfield memory circuit will store at least one vertical scanning period ofthe video signals generated by transmitters 2 or 4 and retrieve thestored video signals for outputting the signals to the switch S1 inconcert with the sequencing rate, on the basis of the synchronizingsignal generated by the synchronizing generator 6B, thereby providing asmooth switching from one television camera to another. The memorycircuit or circuits of the time base corrector 7 will regenerate thefields or frames of the video signals fed by the transmitter 2 or 4,synchronously on the basis of the external sync signals and repeatedlywith every sequencing cycle, and feed the synchronously regeneratedvideo signals to the switcher input terminals 13/1˜13/n.

[0075] It should be noted that the parts of the television camera andthe synchronizing signal generator and/or the time base corrector whichare known have not been described in detail herein because they aredisclosed in the referenced patents.

[0076] As shown in FIGS. 10 and 11, the identification code generators 3and 3A respectively incorporate a counter 86 for counting the number ofthe horizontal scanning lines. The adder input of counter 86 receivesthe horizontal synchronizing signal, generated by the internalsynchronizing signal generator 82, and the clear or reset input of thecounter 86 receives the vertical synchronizing signal generated by theinternal synchronizing signal generator 82, thereby, the counter 86counts the number of the horizontal scanning lines every field or frameof the vertical scanning period of the television camera 2A or 2B. Theoutput of counter 86 is fed to a gate circuit 88.

[0077] The identification code generator 3 shown in FIG. 11 incorporatesa synchronizing separator 79 for separating the internal synchronizingsignal generated by the television camera 2A or 2B and transmittedthrough the video transmission line 5, for outputting the horizontalsynchronizing pulses and the vertical synchronizing pulses to thecounter 86. Therefore, the identification code generator 3, shown inFIG. 11 can be placed along the video transmission line, remotely fromthe television camera 2A. If a non-external synchronized camera 2B isused then the comparator circuit 70 and the reference 71 shown in FIGS.9 and 10 are not needed and are not used.

[0078] The gate circuit 88 outputs a gate signal to the code signalgenerator 80 only when the count number in the counter 86 remains at apredetermined value, for a duration of at least one horizontal scanningline period. It is preferable that the predetermined value of thecounter number is within the vertical blanking period, for example, inthe NTSC system the first 21 horizontal scanning lines are within thevertical blanking period, therefore, it is preferable that the gatesignal, generated by the gate circuit 88 is outputted for anypredetermined number of horizontal scanning lines, within, for example,the 9th to the 20th horizontal scanning lines of one vertical scanningperiod.

[0079] The code signal generator 80 is connected to a code settingcircuit 82 for setting the camera identification code; therefore, thecode generator 80 outputs a code signal corresponding to theidentification code, set in the code setting circuit 82, to a codeadding circuit 15 when the gate signal is received and for the durationof the gate signal.

[0080] The identification code set in the code setting circuit 82 isindividually allotted code to each of the transmitters 2, to identifythe video signal generated by the corresponding transmitter 2.Identification code such as numbers, “1”, “2”, “3” . . . “n”, can beused as camera identification code, respectively.

[0081] An apparatus for generating code signals and a circuit forinjecting code signals into the video signal is disclosed in U.S. Pat.No. 4,943,864, the contents of which are incorporated herein byreference, therefore, each of the information signals received by thedigital recorder 30 incorporates identification code.

[0082] The code signal is a binary code or a bar code signal having twoor more levels, composed of a high level or white, which is the maximumlevel of the picture signal in the video signals, a low level or black,which is lowest level of the picture signal, and a median level or gray,which is the mid level of the picture signal in the video signal,generated by the television cameras 2A or 2B as shown in FIG. 15A; theidentification code may be a combination of pulse signal levels andvarying pulse widths as shown in FIG. 15B.

[0083] Alternatively, the code signal may be either a sine-wave signalor a pulse signal having a frequency corresponding to the identificationcode, and the sine-wave or the pulse signal is generated during one ormore horizontal scanning period as shown in FIG. 15C, preferably, duringthe vertical blanking period.

[0084] The code adding circuit 84 superposes the code signal fed fromthe code signal generator 80, into the video signal fed from thecorresponding television camera 2A or 2B, and then outputs a signalcomposed of the code signal superposed in the video signal, to the videotransmission line 5, through the terminal 76, to be connected to theinput of the switch circuit 13/1˜13/n.

[0085] The switch S1 of the recording receiver 11 connects in sequenceand in synchronized rotation the transmitters 2 to the digital recorder30 through the synchronizing pulse clipping circuit 19, on the basis ofthe external synchronizing signal generated by the externalsynchronizing signal generator 6; therefore, the transmitters 2 areconnected in sequence and in rotation to the digital recorder for atleast one vertical scanning period of the video signal.

[0086] The switch S1, may be an electronic switching circuit using wellknown switching technic by employing readily available ICs, or byemploying discrete circuit using transistors, resistors and diodes. Theswitching timing can be controlled by separating the synchronizingsignals from the video signals by well known sync separators andcontrolling the switching timing on the basis of separated synchronizingpulses, or controlling the switching timing by the field or frame pulsegenerated by the external synchronizing generator 6.

[0087] The receiving means 10B and 10D of FIGS. 4 and 6, respectively,comprising the recording receivers 11B and 11D and transmitters 4 and4B, respectively, incorporate an identification code generator 14 and acode adding circuit 15 which are essentially identical to theidentification code generator 3 with the exception that a range ofpreprogrammed codes are inputted into the code setting circuit 82 shownin FIG. 11 and in accordance to data fed from the switch pole 12 viaterminal 82A, the code setting circuit will generate an individual codein accordance with the pole 12 position, i.e., to which input it isconnected, for feeding one of the preprogrammed codes through the codeadding circuit 15 to the video signal; therefore, each individualsequencing signal will be added with an individual identification code,allotted to the individual transmitter 2 connected to an input 13/1˜13/nof the switch S1.

[0088] The plurality of transmitters 2 connected to the recordingreceiver 11E of the receiving means 10E shown in FIG. 7 are notexternally synchronized and each television camera 2B feeds the videosignals including the identification codes to the processor and compresscircuit 8 through the transmission lines 5. The processor and compresscircuit comprises a well known circuit that receives, processes andcompress a video signal and feeds a digitally compressed video signal,such as the well known JPEG, MPEG, MPEG2 or similar and the digitallycompressed signals are outputted individually and fed through theconnecting lines 5E to a well known parallel-to-serial converter 9 andthe serially outputted, digitally compressed signals are fed through thevideo out terminal 18 to the digital recorder 30 for storing thedigitally compressed signals, along with the time and date and theidentification numbers of the processed camera signals.

[0089] For identifying the identification code the processor andcompress circuit 8 further comprises a code extractor circuit 100 shownin FIG. 13. The code extractor circuit receives the video signal throughterminal 101 and feeds the received signal to a synchronizing separator102 and to a gate circuit 106. The synchronizing separator feeds thehorizontal and vertical sync to a sync counter 104 that counts thehorizontal lines to a predetermined value or values in the same way thecounter 86 of FIG. 11 counts the horizontal lines and feeds gate-onsignal to the gate circuit 106 during the predetermined countedhorizontal line or lines for switching on the gate circuit 106 to passthe video signal to a level sensor 108. The level sensor 108 thereby isfed with the video signal portion that contains the coded identificationfor detecting its envelope or shape and outputting the extracted codethrough an output terminal 109 to be processed by the processor andcompress circuit 8.

[0090] The plurality of transmitters 4B of the receiving means 10F shownin FIG. 8 contain no identification code generator and similarly to thetransmitters 2 of FIG. 7, the television cameras of the transmitters 4Bare not externally synchronized and they output video signals withoutidentification codes to the processor and compress circuit 4B. A wellknown digital processor 8F is fed separately by an identification codegenerator 14F with preprogrammed identification codes assigned to eachof the transmitters 4B and it processes the identification codes alongwith the compressing of the video signals, such that each individualcompressed signal is fed with the identification code to the input ofthe parallel-to-serial digital converter 9.

[0091] The parallel to serial digital converter of the recordingreceiver 11F shown in FIG. 8 feeds to the digital recorder 30 withserially sequencing compressed signals the same way the parallel toserial converter 9 of the recording receiver 11E does.

[0092] It becomes obvious that any of the receiving means 10, 10A, 10B,10C, 10D, 10E and 10F will output sequencing synchronous or compressedserial video signals and each of the individually sequencing signalsincorporates an allotted identification code number for recording,storing and retrieving the signals on the basis of the signalidentification code.

[0093] The digital video recorder 30 shown in FIG. 16 comprises a CPU(Central Processing unit) 40 comprising a well known microprocessorcircuit or a personal computer (PC), one or more memory storage devices,such as the well known HDD (Hard Disk drive) 32 and at least oneremovable or swappable memory storage device 33, such as HDD or the wellknown DVD disk or CD disk drive.

[0094] The CPU 40 comprises a well known compress/decompress circuit orsoftware package 43 for compressing the video signal fed to digitalrecorder through its video input terminal 31 employing any one of thewell known compression formats such as JPEG, MJPEG, WAVELET, MPEG,MPEG1, MPEG2, MPEG4 or similar format and for feeding the compressedsignals along with the time and date and the identification code of theprocessed signal to the HDD 32 memory storage devices through an HDDsystem control 49.

[0095] The well known HDD system control, using hard disk managementsoftware, such as used with personal computer (PC), manages the HDD 32drives, so as to feed the HDD 32 to its maximum capacity and when morethan one HDD 32 are employed, to feed all the HDD 32 drives one afteranother, each to its maximum capacity. When the last HDD32 n is fullwith no capacity left to continue the recording, the HDD system control49 will feed the freshly compressed signal into the first HDD 32 devicefor storing the freshly compressed signals by removing the oldest storedcompressed signals, in a rotation known as FIFO (First In First Out).

[0096] Whenever an alarm signal is fed through an alarm-in terminal 38to a controller 41 of the CPU 40 the controller feeds an alarm statecommand to the HDD system control so as to continue recording andstoring the compressed video signals, in a routine FIFO storing manner,and when the alarm is cleared transfer the compressed video signals thatwere stored during the alarm state, plus n time duration of pre alarmand/or post alarm stored signals to the removable/swappable memorystorage device 33. It is preferable that the transfer of the storedcompressed video signals to the removable/swappable memory storagedevice is actually a reproduction or duplication of the storedcompressed signals, leaving the routinely recorded and stored signals inits original form, in order not to disrupt the FIFO recording integrity,so as to maintain an undisturbed recording in simple FIFO rotationthroughout the time, yet to provide a separate long term or permanentstorage means for the alarm state recording, or as selected by the user,the alarm state recording plus an n time of pre alarm and/or post alarmrecording.

[0097] Similarly to the alarm recording process it is possible totransfer in the same manner any particular recorded event by a manualcommand through a selector keyboard 39 shown in FIG. 1, or by setting aprogram for an automatic, timer control command to transfer particularrecording during a user selectable time and date and for a userselectable n time duration, etc.

[0098] The CPU 40 further comprises a video output circuit 47 forprocessing a decompressed video signal for superposing time and date,and/or identification code number and/or, name or text and a circuit 45for decoding/encoding the identification code and/or the time and dateand/or the alarm particulars.

[0099] The decoding portion of the I.D and T/D decoder/encoder circuit45 can be a circuit such as the circuit 100 of FIG. 14, wherein thevideo signals are fed through the input terminal 101 and the extractedcode outputted from the output terminal 109 is fed to the controller 41,and to the HDD system control 49 and to the compress/decompress circuit43 for further processing and for feeding the decoded identificationcode along with the compressed signal for storage into the HDD memorydevices 32.

[0100] An encoding circuit portion 90 of the ID and T/D encode/decodecircuit 45 shown in FIG. 14 comprises a horizontal sync counter 94 forcounting the horizontal lines of the decompressed video signal on thebasis of the horizontal and vertical sync pulses fed from the decompresscircuit 43 for counting the horizontal line or lines and feeding gate-onsignal during a predetermined count of horizontal line or lines. In thefollowing description, the identification code is injected into singlehorizontal line 11 or into dual horizontal lines 11 and 12, the time anddate are injected into three horizontal lines 14 to 16, and the alarmparticulars are injected into single horizontal line 18 or dualhorizontal lines 18 and 19. Accordingly the horizontal sync counter 94counts line 11 or lines 11 and 12 and feeds gate-on signal to the gate96 for the period of line 11 or lines 11 and 12. The gate 96 transfersduring line 11 or lines 11 and 12 the identification code from the codegenerator 92 to the code adding circuit 98 of the video output circuit43, and the code adding circuit 98 injects the identification code intothe video signal. When the horizontal sync counter 94 counts lines 14 to16 it generates a gate on command to the gate 96 for transferring a timeand date code which can, for example, be a binary number comprising theaccumulative number of seconds, with the Jan. 1, 2000 is zero andincreasing incrementally with each passing second by one, thereby theseconds count, for example, for Jan. 10, 2001 at 24.00 hr. will be; 375days×24 hours×60 minutes×60 seconds=32,400,000 seconds, accordingly, thecontrol unit will feed to the code generator the accumulative number ofseconds, of the actual time and date of the recording of the signal andthe code generator 92 will convert the number into a binary code, or abar code, the same way the identification code is generated and willfeed the code to the code adding circuit 98 for injecting the time anddate code into the video signal, during horizontal lines 14, 15 and 16.When the horizontal sync counter 94 counts the horizontal line 18 orlines 18 and 19 and if the recalled signal was recorded during an alarmstate, the controller will feed a preprogrammed data such as the alarmlocation, its number and other particulars to the code generator whichconverts the data into binary code, or bar code and feeds the code tothe code adding circuit 98 for injecting the alarm particulars duringthe horizontal line 18 or lines 18 and 19. By such arrangement theoutput video signal fed from the digital recorder can be propagatedfreely to a playback receiving stations for displaying a clean pictures,unobstructed by a superimposed text and/or time-date and/or otherdisplays that commonly cover important portions of the displayedpicture.

[0101] In the preferred embodiment of the present invention, the addingcircuit 15 or 98 may include a mixer circuit wherein the code signalsare mixed and injected into the video signal. Such mixer circuit isdisclosed in U.S. Pat. No. 4,989,085, the contents of which areincorporated herein by reference, or it can be an injection circuitdisclosed in U.S. Pat. No. 5,335,014, the contents of which areincorporated herein reference.

[0102] As shown in FIG. 14, the code is also fed through the gate 96 toa memory circuit 97 and to an OSD (On Screen Display) circuit 99 of thevideo output circuit 47. The memory circuit 97 contains the names, textand alarm particulars related to each allotted identification code andto each alarm signal and/or other particulars of the alarm locationsetc, for feeding the data to the OSD circuit 99 and upon commandreceived from the controller 41 the OSD circuit 99 switches off, or onfor superimposing onto the picture a display of the time/date of therecording, and/or identification number and/or name and/or text and/oralarm details. The control circuit 41 command can be automaticallyactivated during programmed events or during alarms, or can be manuallyactivated through the selector keyboard 39 shown in FIG. 1. Further thememory circuit 97 can be used to store graphics pertaining, such as alocation of a camera or of an alarm sensor and feed such graphic data tothe OSD circuit 99 for superimposing onto the picture on screen graphicdisplays.

[0103] The selector 39 shown in FIG. 1 can be a keyboard with indicatorsor with a display such as LCD for generating select command through thecontrol-in terminal 33 and for receiving data pertaining the time anddate of the recording, and/or the alarm details and/or theidentification number or numbers of the stored and/or the played backsignals, etc through the control-out terminal 36.

[0104] The controller 41 (shown in FIG. 16) of the CPU 40 using a wellknown microprocessor circuit updates throughout the time its data,pertaining the time and date of the routinely cascaded and the alarmrecordings and thereby can provide through the control-out terminal 36detailed data of the location of the recorded files within the cascadedHDD drivers 32 as well as access instantly the recorded files forplaying back the selected signals upon command.

[0105] When the digital video recorder 30 is fed from a receiving means10E or 10F with digitized, serially compressed signals the CPU willprocess and transfer the signals directly to the HDD memory means 32 forstorage without activating the compress/decompress circuit 43 for thecompressing process. The compress/decompress circuit 43 however will beactivated for decompressing the stored signals for playing back thesignals and outputting decompressed video signal to the video outputcircuit 47.

[0106] Shown in FIG. 17 are n number of digital recorders 30 mountedinto a rack 50 for increasing the storage capacity by combining thedigital recorders 30 into a cascaded chain wherein a first digitalrecorder 30 DVR1 is connected via its control-in terminal 35 to acascade control 52 of the DVR rack 50. The control-out terminal 36 ofthe DVR1 is connected to control-in terminal 35 of DVR2 and control-outterminal 36 of DVR2 is connected in a cascaded chain to control-interminal 35 of DVRn. The control-out terminal 36 of DVRn is connected inreturn to the cascade control 52, completing the closed looped cascadedcontrol connection.

[0107] The alarm input terminal 57 of the cascade control 52 replacesthe individual alarm connection 38 of each digital recorder shown inFIG. 16.

[0108] Each individual video input terminal 31 of each digital recorderis connected to a video distribution amplifier 54 of the DVR rack 50 andeach output 37 is connected to the video output selector 56. The inputof the distribution amplifier is connected to the output of the receiverof a receiving means 1 shown also in FIG. 1. The output of the videoselector 56 is fed to an input of a playback receiver 70A, which iscontrolled by a selector 39 and feeds its output to a monitor 60. Thecascaded control 52 comprises a well known microprocessor and memorycircuits for registering the time and date of the on-going cascadedrecording of each DVR in the rack, and the time and date of all thereceived alarm signals and their particulars for addressing and feedingthe received alarm signals to the current recording DVR in the cascadedchain and for communicating with the playback receiver 70A whileaddressing the video output selector 56 for connecting the selected DVR,on the basis of the registered time and date to the playback receiver,for feeding a playback of a serially sequencing signals or a specificcamera signal on the basis of the camera identification code.

[0109] The video distribution amplifier is a well known distributionamplifier for feeding video signals fed from the receiving means 10 and10B to all the video inputs of the DVRs in the cascade of a rackassembly 50. When recording receivers 11E or 11F of the receiving means10E or 10F are connected to a DVR rack, such as the receiving means 10Fshown in FIG. 19 is connected to DVR rack assembly n, a digital bufferamplifier is used instead of the video distribution amplifier 54.

[0110] The cascade control in-out provides for instant addressing to allthe CPUs of the DVRs in the cascade and for processing all data and forintercommunicating during a shift in the recording from one fullyrecorded DVR to next DVR in the cascade, as well for maintaining unifiedtime and date throughout the system. For simplifying the addressing forboth, the recording and the playback, each of the DVRs is allotted withexclusive station code or number, thereby expanding the recall to a timeand date, and/or the exclusive identification number of the selectedcamera signal, and/or the selected DVR exclusive station number and/orthe alarm particulars.

[0111] The selector 39 can also transfer a specific recording orplayback commands to the cascade control 52 through the playbackreceiver 70A, such as, recording transfer command of a selected time anddate of a selected camera signal or signals, or playback commands suchas fast forward or fast rewind search, or step by step playback of anindividual camera signal, on the basis of the identification code andthe like.

[0112] The cascade control 52 can feed to the playback receiver 70Aand/or to the selector 39 data pertaining the particulars of a selectedalarm or alarms, the time and date of the recordings, the location ofthe recording, i.e., the specific DVR or the specific HDD in which thestorage is located, etc for superposing such data upon command onto themonitor 60 or to a display panel or to indicators of the selector 39,thereby simplifying the operator's selection process. By thisarrangement it becomes obvious that it is possible to use a receivingmeans 10˜10F for generating and feeding multiple, synchronouslysequencing video signals, or multiple serially processed compressedvideo signals each allotted with an identification number to a multipledigital recorders 30 connected in a simple cascade for increasing theoverall capacity of the recording system, and playing back any of therecorded signals instantly on the basis of time and date, the allottedidentification number or a particulars of an alarm and/or the allottedstation code number to the digital video recorders.

[0113] The playback receiver 70A shown in FIG. 18 consists of a codeextracting circuit 100 shown in FIG. 13 for extracting theidentification code from the received video signal through the inputterminal 101 and for feeding the extracted identification to a playbackcontrol circuit 71. The code and sync extracting circuit 100 furtheroutputs the sync separated by the sync separator 102 of FIG. 13 throughthe terminal 103 to the video buffer memory circuit 74. The video buffermemory circuit 74 is fed with a selective video or sequencing videosignals through the output terminal of the playback control circuit 71,which is fed with played back signals through a selector switch S70. Theplayback control will generate a selective video signal and feed it tothe video buffer memory 74 only when the extracted code, extracted bythe code extraction circuit 100 fed to it and the select code fed by theselector 34 are a match code. A match code signal is also fed to thevideo buffer memory 74 from the playback control for opening the memoryinput, for freshly inputting or for renewing the storing of a videosignal of at least one vertical scanning period of the video signal, fedto the video buffer memory 74 through terminal 79.

[0114] Therefore, the match signal generated by the playback control 71will start a renewed storing by the memory circuit 74 of at least onefield or frame of the video signal which is superposed with anidentification code that corresponds to the selected code, set by theselector 39.

[0115] Since the stored video signal in the memory circuit 74 is renewedonly when the match signal is generated by the playback control 71, thevideo signal generated by the memory circuit 74 for outputting to thevideo output circuit 73 and monitor 60 shown in FIG. 1, remains sameuntil another match signal is generated by the controller 71, and thememory storage is renewed by a freshly inputted video signal.

[0116] Even though the memory signal remains same for one or more fieldsof frames, the same memorized signal is generated every field on thebasis of the separated sync signal fed by the code and sync extractioncircuit 100 to the video buffer memory 74.

[0117] Therefore, the image appearing on the monitor 60 remains same fora period of one sequencing rotation time, and until the video signalsuperposed with the same identification code signal is played back bythe digital video recorder 30, at which time, a renewed image willappear on the monitor 60.

[0118] It is also possible to feed the video buffered memory 74 withmultiple camera signals by selecting multiple identification codesthrough the selector 34 and upon command by the selector through theplayback control 71 combine several camera signals into one display suchas the well known quad, 9 split or 16 split displays, or the well knownpicture in picture displays, etc. Further, as it is possible to recall aspecific single camera signal through the digital video recorder 30 itis not necessary to process such individual played back signal throughthe video buffer memory 74, and therefore upon command generated by theselector 34 for selecting a playback that requires no additionalprocessing by the video buffer memory 34 the playback control 71 willfeed the video buffer memory 34 with a bypass command in order totransfer the played back video signal to the video output circuit 73 asis.

[0119] The video output circuit 73 is similar to the video outputcircuit 47 of the digital recorder 30 of FIG. 16, comprising of an OSD(on screen display) for displaying upon command onto the picturedisplayed on the monitor 60, the time and date of the recording and/orthe identification code and/or name and/or text and/or the alarmparticulars, all fed from the playback control 71 on the basis of datastored in system memory 72.

[0120] The system memory 72 can also be fed manually or automaticallyvia the playback control with data pertaining the transmitters 2 or 4and/or the data pertaining the alarm sensing particulars of eachindividual receiving means 10˜10F and each digital recorder means 30 andeach digital recorder rack 50 shown in FIG. 19. By such memorized datathe playback control is able to instantly address the selector S70 toselect the correct input line 78/1˜78/n pertaining a selectedidentification code or codes of a given transmitting means 2 or 4. Whenonly single digital recorder 30 is used, or when only single digitalrecorder rack 50 is used the selector switch S70 is not used and is notnecessary.

[0121] The playback control 71 is further provided with data in-outterminal or terminals 77/1˜77/n for transmitting record or playbackselect commands to the cascade control 52 of the digital recorder racksand for receiving data pertaining the recording and/or playback and/oralarms particulars.

[0122] By the use of the playback receiver it becomes clear that with asimple cascaded connections of a plurality of digital video recorders 30mounted onto a plurality of video recorders racks it is possible,according to my invention, to record the signals of large number ofcameras onto large number of digital recorders for an extended time, bya simple multiple FIFO rotations, and storing alarm related camerasignals onto a separate memory storage devices for a long or forpermanent storing, and retrieving instantly any of the recorded signalsby a simple select command of a time and date, camera identificationand/or alarm particulars. It is further obvious that by providing thedata pertaining the camera identification, the time and date of therecording and the alarm particulars inside the vertical blanking portionof the video signals it is possible to propagate a clean unobstructedplayback signals and superimpose the data onto the picture by anoperator command only when it is needed.

[0123] It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and that it isintended to cover all changes and modifications of the example of theinvention herein chosen for the purpose of the disclosure, whichmodifications do not constitute departures from the spirit and scope ofthe invention.

What is claimed is:
 1. A method for processing and recording videosignals generated by a plurality of externally synchronized videotransmitters and propagated via a video transmission line to a recordingreceiver, said recording receiver including an external synchronizinggenerator for propagating an external synchronizing signal to saidtransmitters via a transmission line, an identification code generatorfor mixing each of said video signals with an individually allottedidentification code signal and a synchronous switch for outputting saidvideo signals synchronously in sequence on the basis of said externalsynchronizing signal to a digital recorder having at least one mainmemory storage device for routine recording of said video signals inendless sequence rotation, and at least one exclusive memory device forretaining said video signals recorded during an alarm state and an alarmdata signal input for triggering said alarm state, the method comprisingthe steps of: extracting said identification code from each sequencingindividual video signal, for compressing and routinely storingcompressed individual video signals one after another in sequence alongwith the extracted identification code thereof, on the basis of the timeand date of said routine recording, into said at least one main memorystorage device, one after another, each to its capacity, in endlesscascaded rotation, wherein freshly recorded signals replace the oldeststored signals; and at least one of duplicating and transferring saidsignals recorded during said alarm state to said at least one exclusivememory device, thereby retaining and protecting said signals recordedduring said alarm state from routine replacement by said freshlyrecorded signals.
 2. The method as set forth in claim 1 which forsynchronizing said plurality of transmitters, further comprises thesteps of: transmitting a pulse signal having a voltage level higher thana maximum voltage level of said video signals or lower than a minimumvoltage level of said video signals to respective transmitting meansover said video transmission line as an external synchronizing signal byusing blanking level portions of the video signals; separating saidpulse signal transmitted over said transmission line from said videosignals by comparing said video signals to a reference signal having apredetermined voltage level; and applying said separated pulse signal torespective transmitting means.
 3. The method as set forth in claim 2,wherein said pulse signal is opposite in polarity to an internalsynchronizing signal which is contained in each of said video signals.4. The method as set forth in claim 1, which for synchronizing saidplurality of transmitters further comprises the steps of: transmittingan external synchronizing signal selected from one of a horizontal andvertical drive signal, a vertical drive signal, a composite signal, ahorizontal signal and a vertical signal over said transmission line; andreceiving said signal transmitted over said transmission line andapplying said signal to respective video transmitters.
 5. A method forprocessing and recording video signals generated by a plurality ofnon-synchronized video transmitters and propagated via a videotransmission line to a recording receiver, said recording receiverincluding a time base corrector, an external synchronizing generator forapplying an external synchronizing signal to said time base correctorfor outputting said video signals synchronizing in sequence, anidentification code generator for mixing each of said video signals withan individually allotted identification code signal, and a synchronousswitch for outputting said video signals synchronously in sequence onthe basis of said external synchronizing signal to a digital recorderhaving at least one main memory storage device for routine recording ofsaid video signals in endless sequence rotation, and at least oneexclusive memory device for retaining said video signals recorded duringan alarm state and an alarm data signal input for triggering said alarmstate, the method comprising the steps of: extracting saididentification code from each sequencing individual video signal, forcompressing and routinely storing compressed individual video signalsone after another in sequence along with the extracted identificationcode thereof, on the basis of the time and date of said routinerecording, into said at least one main memory storage device, one afteranother, to its capacity, in endless cascaded rotation, wherein freshlyrecorded signals replace the oldest stored signal; and at least one ofduplicating and transferring said signals recorded during said alarmsstate to said at least one exclusive memory device, thereby retainingand protecting said signals recorded during said alarm state fromroutine replacement by said freshly recorded signals.
 6. The method asset forth in claim 1, which for mixing said identification code signalwith said video signal further comprises generating said individuallyallotted identification code for each individual signal of said videosignals for injecting said individually allotted code into one of saidtransmitters, anywhere along said video transmission line, and at aninput of said synchronous switch.
 7. The method as set forth in claim 6,which for mixing said identification code signal with said video signal,further comprises generating plurality of said individually allottedidentification codes for the plurality of said transmitters andinjecting said individually allotted identification codes into saidoutputted video signals on the basis of each sequencing step of saidsynchronous switch.
 8. The method as set forth in claim 1, wherein saidalarm data signal is combined with said recorded signals during saidalarm state.
 9. The method as set forth in claim 1, wherein said step ofat least one of duplicating and transferring said signals recordedduring said alarm state to said at least one exclusive memory devicefurther comprises extending said step of at least one of duplicating andtransferring recorded signals to include signals recorded prior to saidtriggering of said alarm state and after said alarm state has beencleared.
 10. The method as set forth in claim 1, further comprises thestep of; at least one of duplicating and transferring any of said storedsignals by selecting one of the time and date of recording of saidstored signals, said identification code, and said alarm data signal tosaid at least one exclusive memory device, thereby retaining andprotecting said any of said stored signals from routine replacement bysaid freshly recorded signals.
 11. A method as set forth in claim 1 andadapted for playing back said routinely stored signals and said signalsrecorded during said alarm state, the method further comprising thesteps of: retrieving said stored signals from said at least one mainmemory storage device and said at least one exclusive memory device onthe basis of said time and date of the routine recording of at least oneof said stored signals said stored identification code, and said alarmdata signal; and decompressing the retrieved signals and re-injectingsaid identification code signals, with or without the time and datesignals of the time and date of the recording of said retrieved signals,and with or without said alarm data signal into the vertical blankingportion of the decompressed video signals for outputting saiddecompressed video signals to one of a monitor and a playback receiver.12. The method as set forth in claim 11, and further comprisingextracting at least one of the injected identification code, said timeand date and said alarm data signal from said decompressed video signalsfor superimposing, upon command, said at least one of said code, saidtime and date and said alarm data signal onto a picture displayed onsaid monitor.
 13. The method as set forth in claim 12, wherein saiddigital recorder further includes a directory memory for storing textsor names on the basis of said identification codes and the methodfurther comprises retrieving a text or name from said directory memoryon the basis of said code for superimposing upon command said text orname onto said picture displayed on said monitor.
 14. The method as setforth in claim 11, and further comprising combining a plurality of saiddecompressed video signals retrieved on the basis of at least one ofsaid time and date and a plurality of said identification codes fordisplaying on command onto said monitor, one of a split picture and amulti-screen picture selected from the group consisting of a picture inpicture, quad picture, 9 split picture, 16 split picture and acombination thereof.
 15. The method as set forth in claim 1, and furthercomprising cascading a plurality of said digital recorders for enlargingthe total recording capacity, wherein each of said cascaded digitalrecorders records to a capacity thereof one after another in endlessrotation, and wherein freshly processed signals replace the oldeststored signals.
 16. The method as set forth in claim 15, which furthercomprises the steps of: retrieving any stored signals from any of saidcascaded digital recorders on the basis of said at least one of time anddate of the recording of at least one of the retrieved signals, saidstored identification code and said alarm data signal; decompressingsaid retrieved signals and re-injecting said identification codesignals, with or without the time and date signals of the time and dateof the recording of said retrieved signals, and with or without saidalarm data into the vertical blanking portion of the decompressed videosignals for outputting said decompressed video signals to one of amonitor and a playback receiver.
 17. The method as set forth in claim11, adapted for playing back said routinely stored signals and saidsignals recorded during said alarm state through said playback receiverand further comprising the steps of: extracting from said decompressedvideo signals at least one of said re-injected time and date of therecording, said re-injected identification code or codes saidre-injected alarm data; and selecting video signals for playback on thebasis of said at least one of said extracted code, said time and date ofthe recording and said alarm data, and outputting selected video signalsto a monitor.
 18. The method as set forth in claim 17, and furthercomprising applying at least one of the extracted identification codesaid time and date of the recording and said alarm data signal forsuperimposing upon command, one of said code, said time and date andsaid alarm data onto a picture displayed on said monitor.
 19. The methodas set forth in claim 17, wherein said playback receiver furtherincludes a directory memory for storing texts or names on the basis ofsaid identification codes and the method further comprises retrieving atext or name from said directory memory on the basis of said code andsuperimposing upon command said text or name onto a picture displayed onsaid monitor.
 20. The method as set forth in claim 17, and furthercomprising combining a plurality of said retrieved video signals on thebasis of said time and date and a plurality of said identification codesfor displaying on command, onto said monitor one of a split picture anda multi-screen picture selected from the group consisting of a picturein picture, quad picture, 9 split picture, 16 split picture and acombination thereof.
 21. The method as set forth in claim 16, adaptedfor playing back at least one of said routinely stored signals and saidsignals recorded during said alarm state through said playback receiverand further comprising the steps of: extracting from said decompressedvideo signal said at least one of said re-injected time and date of therecording, said re-injected identification code and said re-injectedalarm data signal; and selecting video signals for playback on the basisof said at least one of said extracted code, said time and date of therecording and said alarm data, and outputting selected video signals toa monitor.
 22. The method as set forth in claim 21, further comprisingapplying said at least one of the extracted identification code, saidtime and date of the recording and said alarm data, for superimposingupon command, said at least one of said code, said time and date andsaid alarm data onto a picture displayed on said monitor.
 23. The methodas set forth in claim 22, wherein said playback receiver furtherincludes a directory memory for storing texts or names on the basis ofsaid identification codes and the method further comprises retrieving atext or name from said directory memory on the basis of said code andsuperimposing upon command said, text or name onto said picture.
 24. Themethod as set forth in claim 21, further comprising combining aplurality of said retrieved video signals on the basis of said time anddate and on the basis of a plurality of said identification codes fordisplaying on command onto said monitor one of a split picture andmulti-screen picture selected from the group of a picture in picture, aquad picture, a 9 split picture, a 16 split picture and a combinationthereof.
 25. A method for processing and recording video signalsgenerated by a plurality of video transmitters and propagated via atransmission line to a recording receiver, said recording receiverincluding a plurality of compression means for compressing said videosignals, an identification code generator for mixing each compressedvideo signal with an individually allotted identification code signal,and a parallel-to-serial converter for serially outputting saidcompressed video signals to a digital recorder having at least one mainmemory storage device for routine recording of said video signals inendless cascaded rotation, and at least one exclusive memory device forretaining said video signals recorded during an alarm state and an alarmdata signal input for triggering said alarm state, the method comprisingthe steps of: extracting said identification code from each individualcompressed video signal, for storing said individual compressed videosignals, routinely one after another along with extracted identificationcodes, thereof on the basis of the time and date of said routinerecording, into said at least one main memory storage device, one afteranother, each to capacity thereof, in endless cascaded rotation, whereinfreshly recorded signals replace the oldest stored signals; and at leastone of duplicating and transferring said signals recorded during saidalarm state to said at least exclusive one alarm memory device, therebyretaining and protecting said signals recorded during said alarm statefrom routine replacement by said freshly recorded signals.
 26. A methodfor processing and recording video signals generated by a plurality ofvideo transmitters and propagated via a transmission line to a recordingreceiver, said recording receiver including a plurality of compressionmeans for compressing said video signals, an identification codegenerator for mixing each video signal with an individually allottedidentification code signal, and a parallel-to-serial converter forserially outputting said compressed video signals to a digital recorderhaving at least one main memory storage device for routine recording ofsaid video signals in endless cascaded rotation, and at least oneexclusive memory device for retaining said video signals recorded duringan alarm state and an alarm data signal input for triggering said alarmstate, the method comprising the steps of: extracting saididentification code from each individual compressed video signal, forstoring said individual compressed video signals, routinely one afteranother along with extracted identification codes thereof, on the basisof the time and date of said routine recording, into said at least onemain memory storage device, one after another, each to capacity thereof,in endless cascaded rotation, wherein freshly recorded signals replacethe oldest stored signals; at least one of duplicating and transferringsaid signals recorded during said alarm state to said at least exclusiveone alarm memory device, thereby retaining and protecting said signalsrecorded during said alarm state from routine replacement by saidfreshly recorded signals, wherein: a code signal commensurate with saidindividually allotted identification code for each individual signal ofsaid video signal is generated and said signal is injected into saidvideo signal within a respective transmitter, or anywhere along saidvideo transmission line, or at the input of said compression means. 27.The method as set forth in claim 25, wherein said alarm data signal iscombined with said recorded signals during said alarm state.
 28. Themethod as set forth in claim 25, wherein said step of at least one ofduplicating and transferring said signals recorded during said alarmsate to said at least one exclusive memory device further comprisesextending said step of at least duplicating and transferring to includerecorded signals recorded at least one of prior to the triggering ofsaid alarm state and after said alarm state has been cleared.
 29. Themethod as set forth in claim 25, and further comprising at least one ofduplicating and transferring any of said stored signals by selecting atleast one of the time and date of the recording of said stored signals,said identification codes and said alarm data to said at least oneexclusive memory device, thereby retaining and protecting said any ofsaid stored signals from routine replacement by said freshly recordedsignals.
 30. The method as set forth in claim 25, and adapted forplaying back said routinely stored signals and/or said signals recordedduring said alarm state and further comprising the steps of: retrievingsaid stored signals from said at least one of said main memory storagedevice and said exclusive memory device on the basis of at least one ofsaid time and date of the recording of said stored signal, said storedidentification code and said alarm data; and decompressing the retrievedsignals and re-injecting said identification code signals, with orwithout the time and date signals of the time and date of the recordingof said retrieved signals, and with our without said alarm data signalinto the vertical blanking portion of the decompressed video signals foroutputting said decompressed video signals to a monitor or to a playbackreceiver.
 31. The method as set forth in claim 30, and furthercomprising extracting at least one of the injected identification code,said time and date and said alarm data signal from said decompressedvideo signals for superimposing upon command said at least one of saidcode, said time and date and said alarm data signal onto a picturedisplayed on said monitor.
 32. The method as set forth in claim 31,wherein said digital recorder further includes a directory memory forstoring texts or names on the basis of said identification codes and themethod further comprises retrieving a text or name from said directormemory on the basis of said code for superimposing upon command saidtext or name onto said picture.
 33. The method as set forth in claim 30,and further comprising combining a plurality of said decompressed videosignals retrieved on the basis of at least one of said time and date, aplurality of said identification codes for displaying on command, ontosaid monitor one of a split picture and a multi-screen picture selectedfrom the group consisting of a picture in picture, quad picture, 9 splitpicture, 16 split picture and a combination thereof.
 34. The method asset forth in claim 25, and further comprising cascading a plurality ofsaid digital recorders for enlarging the total recording capacity,wherein each of said cascaded digital recorders records to its capacityone after another in endless rotation, and wherein freshly processedsignals replace the oldest stored signals.
 35. The method as set forthin claim 34, and further comprising retrieving any stored signals fromany of said cascaded digital recorders on the basis of at least one ofsaid time and date of the recording of the retrieved signal, said storedidentification codes and said alarm data signal, decompressing saidretrieved signals and re-injecting said identification code signals,with our without the tie and date of the recording of said retrievedsignals, and with our without said alarm data into the vertical blankingportion of the decompressed video signals for outputting saiddecompressed video signals to a monitor or to a playback receiver. 36.The method as set forth in claim 30, adapted for playing back at leastone of said routinely stored signals and said signals recorded duringsaid alarm state through said playback receiver and further comprisingthe steps of: extracting from said decompressed video signals said atleast one of said re-injected time and date of the recording, saidre-injected identification code and said re-injected alarm data signal;and selecting video signals for playback on the basis of at least one ofsaid extracted codes said time and date of the recording and said alarmdata signal and outputting selected video signals to a monitor.
 37. Themethod as set forth in claim 36, and further comprising applying atleast one of the extracted identification code said time and date of therecording said alarm data signal for superimposing upon command, said atleast one of said code said time and date and said alarm data signalonto a picture displayed on said monitor.
 38. The method as set forth inclaim 36, wherein said playback receiver further includes a directorymemory for storing texts or names on the basis of said identificationcodes and the method further comprises retrieving a text or name fromsaid directory memory on the basis of said code and superimposing uponcommand said text or name onto said picture.
 39. The method as set forthin claim 36, further comprising combining a plurality of said retrievedvideo signals on the basis of said time and date and on the basis of aplurality of said identification codes for displaying on command, ontosaid monitor one of a split picture and a multi-screen picture selectedfrom the group consisting of a picture in picture, quad picture, 9 splitpicture, 16 split picture and a combination thereof.
 40. The method asset forth in claim 35, adapted for playing back said at least one ofsaid routinely stored signals and said signals recorded during saidalarm state through said playback receiver and further comprising thesteps of: extracting from said decompressed video signal at least one ofsaid re-injected time and date of the recording, said re-injectedidentification codes and said re-injected alarm data; and selectingvideo signals for playback on the basis of at least one of saidextracted codes, said time and date of the recording and said alarm datasignal, and outputting selected video signals to a monitor.
 41. Themethod as set forth in claim 40, and further comprising applying atleast one of the extracted identification code, said time and date ofthe recording and said alarm data signal for superimposing, uponcommand, said at least one of said code, said time and date and saidalarm data onto a picture displayed on said monitor.
 42. The method asset forth in claim 41, wherein said playback receiver further includes adirectory memory for storing texts or names on the basis of saididentification codes and the method further comprises retrieving a textor name from said directory memory on the basis of said code andsuperimposing upon command said text or name onto said picture.
 43. Themethod as set forth in claim 40, and further comprising combining aplurality of said retrieved video signals on the basis of said time anddate and on the basis of a plurality of said identification codes fordisplaying on command, onto said monitor one of a split picture and amulti-screen picture selected from the group consisting of a picture inpicture, quad picture, 9 split picture, 16 split picture and acombination thereof.
 44. An apparatus for processing and digitallyrecording a plurality of video signals comprising: a plurality oftransmitting means for generating video signals; a recording receivingmeans for receiving said video signals, said recording receiving meansincluding a switching means for sequentially connecting said pluralityof transmitting means to a digital video recording means; a plurality ofvideo transmission lines for connecting said plurality of transmittingmeans to said recording receiving means and said switching means;external synchronizing signal generator circuit means for feedingexternal synchronizing signals to said switching means and to saidplurality of transmitting means through a transmission line; each ofsaid transmitting means including an externally synchronized televisioncamera for receiving an external synchronizing signal and for applyingsaid external synchronizing signal to said television camera, therebysynchronizing said television cameras to each other and to saidswitching means; a circuit for generating code signals corresponding toan identification code allotted to each individual said video signal, aninjection circuit for mixing said code signals into said video signal,within said transmitting means, or along said transmission lines, oradjacent to said switching means; the digital video recording meansincluding a central processing circuit including time and date signalgenerating means, an decoding/encoding circuit for receiving said videosignals in sequence for extracting said identification codes from thereceived video signals, and a compression/decompression circuit forcompressing said received video signals and for outputting a compressedsignals along with the respective extracted identification codes thereofand the time and date of the recording to at least one main memorystorage device; said at least one main memory storage device for routinestoring of said compressed signals along with said identification codeand said time and date of the recording into said one or more mainmemory storage devices, for storage in an endless cascaded rotation, oneafter another, each to capacity thereof, wherein freshly stored signalsreplace the oldest stored signals in the cascade; an alarm data signalinput for receiving an alarm signal and for triggering an alarm state;and at least one exclusive memory storage device for retaining saidvideo signals recorded during said alarm state, wherein said routinerecording during said alarm state of said compressed signals along withsaid identification codes and said time and date of the recording issubjected to at least one of duplication and transfer to said at leastone exclusive memory storage device, thereby retaining and protectingsaid recording during the alarm state from routine replacement by saidfreshly stored signals.
 45. An apparatus for processing and recordingplurality of video signals as set forth in claim 44, wherein saidexternal synchronizing signal generator circuit means is connected to atleast one of respective ones of said video transmission lines andadjacent to said switching means, for generating a pulse signal having avoltage level higher than a maximum voltage level of said video signalsgenerated by the respective transmitting means or lower than a minimumvoltage level of said video signal; each said externally synchronizedtelevision camera including a comparator circuit means associatedrespectively with said television cameras for separating said pulsesignal transmitted over said video transmission lines from said videosignals by comparing said video signals to a reference signal having apredetermined voltage level, and applying said separated pulse signal tosaid television cameras associated with said comparator circuit means,thereby synchronizing said television cameras to each other and to saidswitching means.
 46. The apparatus for processing and digitallyrecording plurality of video signals as set forth in claim 45, whereinsaid pulse signal is opposite in polarity to an internal synchronizingsignal which is contained in each of said video signals.
 47. Theapparatus for processing and digitally recording plurality of videosignals as set forth in claim 44, wherein said external synchronizingsignal generator circuit means generates the external synchronizingsignal selected from the group consisting of a horizontal and verticaldrive signal, a vertical drive signal, a composite signal, andhorizontal and vertical signal over said transmission line.
 48. Anapparatus for processing a digitally recording plurality of videosignals comprising: a plurality of non-synchronized transmitting means-for generating video signals; a recording receiving means for receivingsaid video signals, said recording receiving means including a switchingmeans for sequentially connecting said plurality of transmitting meansto a digital video recording means and a time base corrector; aplurality of video transmission lines for connecting said plurality oftransmitting means to said recording receiving means and said switchingmeans; external synchronizing signal generator circuit means for feedingexternal synchronizing signals to said switching means and to said timebase corrector through a transmission line, said time base correctorcorrecting a time base of the receiving video signals on the basis ofsaid external synchronizing signals fed to said time base corrector;each of said transmitting means including a television camera forreceiving an external synchronizing signal and for applying saidexternal synchronizing signal to said television camera, therebysynchronizing said television camera to each other and to said switchingmeans; a circuit for generating code signals corresponding to anidentification code allotted to each individual said video signal; aninjection circuit for mixing said code signals into said video signalwithin said transmitting means, or along said transmission lines, oradjacent to said switching means; a digital video recording meansincluding a central processing circuit including time and date signalgenerating means, an decoding/encoding circuit for receiving said videosignals in sequence for extracting said identification codes from thereceived video signals, and a compression/decompression circuit forcompressing said received video signals and for outputting a compressedsignals along with the respective extracted identification codes thereofand the time and date of the recording to at least one main memorystorage device; said at least one main memory storage device for routinestoring of said compressed signals along with said identification codesand said time and date of the recording into said at least one mainmemory storage device, for storage in an endless cascaded rotation, oneafter another, each to capacity thereof, wherein freshly stored signalsreplace the oldest stored signals in the cascade; an alarm data signalinput for receiving an alarm signal and for triggering an alarm state;and at least one exclusive memory storage device for retaining saidvideo signals recorded during said alarm state, wherein said routinerecording during said alarm state of said compressed signals along withsaid identification codes and said time and date of the recording issubjected to at least one of duplication and transfer to said at leastone exclusive memory storage device, thereby retaining and protectingsaid recording during the alarm state from routine replacement by saidfreshly stored signals.
 49. The apparatus for processing and digitallyrecording plurality of video signals as set forth in claim 44, whereinsaid circuit for generating code signals generates a plurality of saidcodes allotted to each individual video signal for mixing a selectedindividual code with said video signals through said injection circuitby injecting said codes into an output pole of said switching means; andwherein a data signal indicative of position status of said switchingmeans is fed to said circuit for generating code signals for generatinga selected code, commensurate with the identification code allotted to avideo signal connected to said output pole.
 50. The apparatus forprocessing and digitally recording plurality of video signals as setforth in claim 44, wherein said alarm data signal is fed to saiddecode/encode circuit for mixing said alarm data signal with saidrecorded signals during said alarm state.
 51. The apparatus forprocessing and digitally recording plurality of video signals as setforth in claim 44, wherein said recorded signals subjected to at leastone of duplication and transfer, recorded during said alarm state, tosaid at least one exclusive memory storage device are extended toinclude stored signals, recorded at least one of prior to saidtriggering of said alarm state and after said alarm state has beencleared.
 52. The apparatus for processing and digitally recordingplurality of video signals as set forth in claim 44, wherein saidrecorded signals subjected to at least one of duplication and transferinclude any of said recorded signals by selecting at least one of thetime and date of the recording of said recorded signals saididentification codes and said alarm data to said at least one exclusivememory storage device, thereby retaining and protecting said any of saidrecorded signals from routine replacement by said freshly recordedsignals.
 53. The apparatus as set forth in claim 44, and adapted forplaying back said routinely recorded signals and said signals recordedduring said alarm state wherein said central processing circuitretrieves said recorded signals from said at least one main memorystorage device and said at least one exclusive memory storage device onthe basis of at least one of said time and date of the recording of saidrecorded signals, said stored identification codes and said alarm data,and wherein said compression/decompression circuit decompresses therecorded signals and said decoding/encoding circuit re-injects saididentification code signals, with or without the time and date signalsof the recording of said retrieved signals, and with or without saidalarm data, into the vertical blanking portion of the decompressed videosignals for outputting said decompressed video signals to one of amonitor and a playback receiver.
 54. The apparatus as set forth in claim53, adapted for playing back said routinely recorded signals and saidsignals recorded during said alarm state, wherein said encoding/decodingcircuit extracts at least one of injected identification codes, saidtime and date of the recording and said alarm data from saiddecompressed video signals and outputs a signal to a superimposingcircuit for superimposing at least one of said code, said time and dateand said alarm data onto a picture displayed on said monitor.
 55. Theapparatus as set forth in claim 54, adapted for playing back saidroutinely recorded signals and said signals recorded during said alarmstate, wherein said encoding/decoding circuit further comprises adirectory memory for storing texts or names on the basis of saididentification codes for retrieving a text or name from said directorymemory on the basis of said code for superimposing upon command saidtext or name onto said picture.
 56. The apparatus as set forth in claim53, adapted for playing back said routinely recorded signals and saidsignals recorded during said alarm state, wherein said centralprocessing circuit further includes a picture memory circuit forcombining a plurality of said decompressed video signals and outputtinga combined video signal for displaying onto said monitor one of a splitpicture and a multi-screen picture selected from the group consisting ofa picture in picture, a quad picture, a 9 split picture, a 16 splitpicture and a combination thereof.
 57. The apparatus for processing anddigitally recording plurality of video signals as set forth in claim 44,wherein a plurality of said digital recorders are connected in a cascadefor enlarging the total recording capacity; and wherein each of saiddigital recorders connected in the cascade records to its capacity oneafter another in endless rotation, and wherein freshly processed signalsreplace the oldest stored signals.
 58. The apparatus as set forth inclaim 57, adapted for playing back said routinely recorded signals andaid signals recorded during said alarm state, wherein said centralprocessing circuit retrieves said recorded signals from at least one ofsaid main memory storage device and said at least one exclusive memorystorage device on the basis of at least one of said time and date of therecording of said recorded signal, said stored identification codes andsaid alarm data, and wherein said compressing/decompressing circuitdecompresses the recorded signals and said decoding/encoding circuitre-injects said identification code signals, with or without the timeand date signals of the recording of said retrieved signals, and with orwithout said alarm data, into the vertical blanking portion of thedecompressed video signals for outputting said decompressed videosignals to one of a monitor and a playback receiver.
 59. An apparatusfor processing and digitally recording a plurality of video signals,comprising: plurality of transmitting means for generating videosignals; recording receiving means for receiving said video signals,said recording receiving means including a compression means forcompressing said plurality of video signals, an identification codegenerator for mixing each of compressed video signals with individuallyallotted identification code signal, and a parallel-to-serial converterfor serially outputting said compressed video signals to a digital videorecording means; a plurality of video transmission lines for connectingsaid plurality of transmitting means to said recording receiving meansand to said compressing means; said digital video recording meansincluding a central processing circuit comprising time and date signalgenerating means, a decoding/encoding circuit for receiving saidcompressed video signals for extracting said identification codes fromthe received video signals, and a compressing/decompressing circuit foroutputting said compressed video signals along with said extractedidentification codes thereof and the time and date of the recording toat least one main memory storage device; said at least one main memorystorage device operating for routine storing said compressed videosignals along with said identification codes and said time and date ofthe recording into said at least one main memory storage device, inendless cascaded rotation, one after another, each to its capacity,wherein freshly stored signals replace the oldest stored signals in acascade; an alarm data signal input for receiving an alarm signal andfor triggering an alarm state; and at least one exclusive memory storagedevice for retaining said video signals recorded during said alarmstate, wherein said routine recording of said compressed signals alongwith said identification codes and said time and date of the recordingis subjected to one of duplication and transfer to said at least oneexclusive memory storage device, thereby retaining and protecting saidrecording during the alarm state from routine replacement by saidfreshly stored signals.
 60. The apparatus for processing and digitallyrecording a plurality of video signals as set forth in claim 59, whereinsaid identification code generator for mixing said identification codesignal with said compressed signal generates said individually allottedidentification code signal for mixing said code with each individualsignal of said video signals by injecting said individually allottedcode into said transmitters, or anywhere along said video transmissionlines, or at the inputs of said compression means.
 61. The apparatus forprocessing and digitally recording a plurality of video signalsaccording to claim 59, wherein said said alarm data signal is fed tosaid decoding/encoding circuit for mixing said alarm data signal withsaid recorded signals during said alarm data.
 62. The apparatus forprocessing and digitally recording a plurality of video signalsaccording to claim 59, wherein said at least one of said duplication andtransfer of said signals recorded during said alarm state of said atleast one exclusive memory storage device are extended to include storedsignals, recorded prior to said triggering of said alarm state or aftersaid alarm state has been cleared.
 63. The apparatus for processing anddigitally recording a plurality of video signals according to claim 59,wherein said recorded signals subjected to at least one of duplicationand transfer include any of said recorded signals by selecting one ofthe time and date of the recording of said recorded signals, saididentification codes and said alarm data to said at least one exclusivememory storage device, thereby retaining and protecting said any of saidrecorded signals from routine replacement by said freshly recordedsignals.
 64. The apparatus as set forth in claim 59, and adapted forplaying back said routinely recorded signals and said signals recordedduring said alarm state, wherein said central processing circuitretrieves said recorded signals from at least one of said main memorystorage device and said exclusive memory storage device on the basis ofat least one of said time and date of the recording, said storedidentification codes and alarm data; and wherein saidcompression/decompression circuit decompresses the signals and saiddecoding/encoding circuit re-injects said identification code signals,with or without signals of the time and date of the recording of saidretrieved signals, and with or without said alarm data, into thevertical blanking portion of the decompressed video signals foroutputting said decompressed video signals to one of a monitor and aplayback receiver.
 65. The apparatus as set forth in claim 64, adaptedfor playing back said routinely recorded signals and said signalsrecorded during said alarm state, wherein said encoding/decoding circuitextracts at least one of the injected identification code, said time anddate of the recording and said alarm data from said decompressed videosignals and outputs a signal to a superimposing circuit forsuperimposing at least one of said code, said time and date and saidalarm data onto a picture displayed on said monitor fed with saiddecompressed video signals.
 66. The apparatus as set forth in claim 64,adapted for playing back said routinely recorded signals and saidsignals recorded during said alarm state, wherein said encoding/decodingcircuit further comprises a directory memory for storing texts or nameson the basis of said identification codes for retrieving a text or namesfrom said directory memory on the basis of said code for superimposingupon command said text or name onto said picture.
 67. The apparatus asset forth in claim 64 for playing back said routinely recorded signalsand said signals recorded during said alarm state, wherein said centralprocessing circuit further includes a picture memory circuit forcombining a plurality of said decompressed video signals and outputtinga combined video signal for displaying onto said monitor one of a splitpicture and a multi-screen picture selected from the group consisting ofa picture in picture, quad picture, 9 split picture, 16 split pictureand a combination thereof.
 68. The apparatus for processing anddigitally recording plurality of video signals according to claim 59,wherein a plurality of said digital recorders are connected in cascadefor enlarging the total recording capacity; and wherein each of saiddigital recorders connected in the cascade, records to its capacity oneafter another in endless rotation, and wherein freshly processed signalsreplace the oldest stored signals.
 69. The apparatus as set forth inclaim 65, adapted for playing back said routinely recorded signals andsaid signals recorded during said alarm state according to claim 68wherein said central processing circuit retrieves said recorded signalsfrom at least one of said main memory storage device and said recordedsignals from at least one of said main memory storage device and saidexclusive memory storage device on the basis of at least one of saidtime and date of the recording, said stored identification codes andsaid alarm data; and wherein said compressing/decompressing circuitdecompresses the received video signals and said decoding/encodingcircuit re-injects said identification code signals, with or withoutsignals of the time and date of the recording of said retrieved signals,and with or without said alarm data, into the vertical blanking portionof the decompressed video signals for outputting said decompressed videosignals to one of a monitor and a playback receiver.
 70. The apparatusas set forth in claim 58 for processing, digitally recording and playingback a plurality of video signals wherein each of said digital videorecorders is assigned with an exclusive station code and includes meansto enter said station code, said apparatus further comprising: a cascadecontrol means including cascade in-out terminals for interconnectingwith in-out control terminals of said digital recorders connected incascade, an alarm input terminal for receiving and processing alarm datasignals and for communicating an alarm state along with alarmparticulars data to said digital recorders through said cascade in-outterminals and playback control in-out terminals for receiving playbackand display commands and for feeding status data of said time and dateof the recording of any of the recorded signals of said digitalrecorders connected in cascade; video signal distribution means forfeeding said video signals to said digital video recorders connected incascade; video output selector means including a video switch forselecting connecting any of the decompressed output signals fed fromsaid digital video recorders connected in cascade to one of a monitorand a playback receiver; and wherein said central processing meansmanages and updates the time and date of the recording in progress andthe status of said digital video recorders connected in the cascade andretains the data of time and date of the recording of each digital videorecorder connected in cascade and said alarm particulars forcommunicating said updated time and date along with said status and saidalarm particulars to one of said monitor and said playback receiver and;wherein said cascade control means addresses each of said digital videorecorders connected in cascade and said video switch on the basis of atleast one of said updated time and date, said identification code, saidstation code and said alarm particulars.
 71. An apparatus as set forthin claim 69, for processing, digitally recording and playing backplurality of video signals, wherein each of said digital video recordersis assigned with an exclusive station code and includes means to entersaid station code, said apparatus further comprising: cascade controlmeans including cascade in-out terminals for interconnecting with in-outcontrol terminals of said digital recorders connected in cascade, andalarm input terminal for receiving and processing alarm data signals andfor communicating an alarm state along with alarm particulars data tosaid digital recorders through said cascade in-out terminals andplayback control in-out terminals for receiving playback and displaycommands and for feeding status data pertaining said circuit comprisingtime and date signal generating means, a decoding/encoding circuit forreceiving said compressed video signals for extracting saididentification codes from the received signals, and acompressing/decompressing circuit for outputting said compressed signalsalong with said extracted identification codes and the time and date ofthe recording to a memory storage device; one or more main memorystorage devices for routine storing said compressed video signals alongwith said identification codes and said time and date of the recordinginto each said main memory storage device, in endless cascaded rotation,one after another, each to its capacity, wherein freshly stored signalsreplace the oldest stored signals in the cascade; an alarm data signalinput for receiving alarm signal and for triggering an alarm state; anexclusive one or more memory storage devices for retaining said videosignals recorded during said alarm state, wherein said routine recordingof said compressed signals along with said identification codes and saidtime and date of the recording is duplicated and transferred to saidexclusive one or more memory storage devices, thereby retaining andprotecting said recording during alarm state from routine replacement bysaid freshly stored signals.
 72. The playback receiver as set forth inclaim 71, wherein said system memory means further comprises a directorymemory for storing texts or names on the basis of said identificationcodes for retrieving a text or name from said directory memory on thebasis of said code for superimposing upon command said text or name ontosaid picture.
 73. The playback receiver as set forth in claim 72, andfurther comprising a video buffer memory circuit for combining aplurality of said decompressed signals and outputting a combined videosignal for displaying onto the monitor one of a split picture and amulti-screen picture selected from the group consisting of a picture inpicture, quad picture, 9 split picture, 16 split picture and acombination thereof.
 74. The playback receiver as set forth in claim 73,wherein said video output circuit further comprises a superimposingcircuit for superimposing upon select command at least one of said code,said time and date and said alarm data on the basis of at least one ofsaid identification code said time and date of the recording and saidalarm data extracted from said decompressed signals and for outputtingvideo signal and for displaying a superimposed picture onto the monitor.75. The playback receiver as set forth in claim 74, wherein said systemmemory means further comprises a directory memory for storing texts ornames on the basis of said identification codes for retrieving a text orname from said directory memory on the basis of said code forsuperimposing upon command said text or name onto said picture.
 76. Theplayback receiver as set forth in claim 73 and further comprising avideo buffer memory circuit for combining a plurality of saiddecompressed signals and outputting a combined video signal fordisplaying onto a monitor one of a split picture and a multi-screenpicture selected from the group consisting of a picture in picture, quadpicture, 9 split picture, 16 split picture and a combination thereof.77. The playback receiver as set forth in claim 74, wherein said videooutput circuit further comprises a superimposing circuit forsuperimposing upon select command at least one of said code said timeand date and said alarm data on the basis of at least one of saididentification code said time and date of the recording and said alarmdata extracted from said decompressed signals and for outputting videosignal and for displaying a superimposed picture onto the monitor. 78.The playback receiver as set forth in claim 77, wherein said systemmemory means further comprises a directory memory for storing texts ornames on the basis of said identification codes for retrieving a text orname from said directory memory on the basis of said code forsuperimposing upon command said text or name onto said picture.
 79. Theplayback receiver as set forth in claim , and further comprising a videobuffer memory circuit for combining a plurality of said decompressedsignals and outputting a combined video signal for displaying onto themonitor one of a split picture or multi-screen picture selected from thegroup consisting of a picture in picture, quad picture, 9 split picture,16 split picture and a combination thereof.
 80. The playback receiver asset forth in claim , wherein said video output circuit further comprisesa superimposing circuit for superimposing upon select command at leastone of said code said time and date and said alarm data on the basis ofat least one of said identification code, said time and date of therecording and said alarm data extracted from said decompressed signalsand for outputting video signal and for displaying a superimposedpicture onto the monitor.
 81. The playback receiver as set forth inclaim , wherein said system memory means further comprises a directorymemory for storing texts or names on the basis of said identificationcodes for retrieving a text or name from said directory memory on thebasis of said code for superimposing upon command said text or name ontosaid picture.
 82. The playback receiver as set forth in claim , andfurther comprising a video buffer memory circuit for combining aplurality of said decompressed signals and outputting a combined videosignal for displaying onto the monitor one of a split picture and amulti-screen picture selected from the group consisting of a picture inpicture, quad picture, 9 split picture, 16 split picture and acombination thereof.